The increased utilization of electronic devices, in an ever widening array of diverse technologies, such as computers, automotive, medical, and household appliances has led to the operation of many of these electronic devices in harsh environments such as high humidity, high temperatures, or combinations thereof. In addition, there is also an increased demand for reliability. The continued improvement in performance and component density, of semiconductor devices, has led to a rapidly growing demand for packaging technologies to yield packaged devices having reduced cost, improved reliability and performance, increased interconnect density, and small package size.
Typically, a semiconductor device includes a semiconductor die with bond pads formed on its surface, and bond wires that electrically couple the bond pads with lead fingers on a lead frame. The semiconductor die is attached to the lead frame before bonding, and typically a polymer is dispensed or molded around the die, the bond wires, and the majority of the lead frame to encapsulate the device. The device is often electrically coupled with a printed circuit board (PCB) by soldering leads of the lead frame to pads on the PCB. The utilization of some encapsulating polymers can lead to performance degradation and damage from electrical shorting, corrosion, or cracking due to moisture. This tends to be an even greater problem when the electronic device must operate in a harsh environment.
Hermetic sealing using a metal or ceramic package provides an increased level of protection, however, the manufacturing process is complex and results in a more expensive package of increased size. Another method that can be utilized is sealing a semiconductor chip""s active circuitry at the wafer stage, by applying a passivation coating over the active circuitry on the wafer. However, this process may still lead to a non-hermetically sealed device, by causing damage to the ceramic like coating in the vicinity of the bond pads in subsequent processing, thereby permitting corrosion to deleteriously affect chip reliability and life. Further, this process does not provide protection to the bond pads and electrical interconnections. In addition, these technologies do not lend themselves to all applications. For instance, over the past decade, substantial developments have been made in the micromanipulation of fluids, in fields such as electronic printing technology using inkjet printers. The ability to maintain reliable electrical interconnections in such products has become more difficult as the corrosive nature of the fluids increases.
An inkjet print cartridge provides a good example of the problems facing the practitioner in providing robust electrical interconnections to a semiconductor chip operating in a harsh environment. There are a wide variety of highly-efficient inkjet printing systems, currently in use, which are capable of dispensing ink in a rapid and accurate manner. Conventionally, electrical interconnections are made using a flexible circuit that has metal beams that extend out from the flexible substrate and are coupled to bond pads located on the inkjet chip. A polymer encapsulant is dispensed onto the coupled bond pads and beams and is then cured.
Ink jet cartridges typically include a fluid reservoir that is fluidically coupled to a substrate that is attached to the back of a nozzle layer containing one or more nozzles through which fluid is ejected. The substrate normally contains an energy-generating element that generates the force necessary for ejecting the fluid held in the reservoir. Two widely used energy generating elements are thermal resistors and piezoelectric elements. The former rapidly heats a component in the fluid above its boiling point causing ejection of a drop of the fluid. The latter utilizes a voltage pulse to generate a compressive force on the fluid resulting in ejection of a drop of the fluid.
In particular, improvements in image quality have led to the use of more complex ink formulations that generally increases the organic content of inkjet inks. The use of such inks, results in a more corrosive environment experienced by the materials coming in contact with these inks. Thus, degradation of the electrical interconnections by these more corrosive inks raises material compatibility issues as well as design issues in order to maintain reliable printheads. In addition, improvement in print speed has typically been gained by utilizing a larger printhead resulting in an increased print swath. The larger printhead typically results in a larger number energy generating elements, which can result in an increase number of electrical interconnections thereby exacerbating the problem. In addition, higher resolution may result in a larger number interconnects, closer spaced, with thinner organic passivation further contributing to reliability issues. Further, in an effort to reduce the cost and size of ink jet printers and to reduce the cost per printed page, printers have been developed having small, moving printheads that are connected to large stationary ink supplies. This development is called xe2x80x9coff-axisxe2x80x9d printing and has allowed the large ink supplies to be replaced as it is consumed without requiring the frequent replacement of the costly printhead containing the fluid ejectors and nozzle system. Thus, the typical xe2x80x9coff-axisxe2x80x9d system often utilizes a semi-permanent or permanent printhead that requires increased reliability and robustness of the electrical interconnections to maintain its optimal performance.
An electronic device includes a substrate, a substrate electrical connector disposed on the substrate, and a carrier lead electrically coupled to the substrate electrical connector. In addition, the electronic device further includes a polymer enclosing the substrate electrical connector, and an inorganic film disposed over the substrate electrical connector in contact with the polymer.